I had an old Raleigh with center pull. It was a wonderful bike. It didn’t use brake cables either; it used mechanical (straight) steel bars instead. Sadly, it was stolen… I think they went to center pull from side pull has to do with the distance from the caliper to the rim. On a side pull the distance is ½ inch or so – the cable went to side of the caliper and the caliper itself was pretty small, so more pressure could be applied to the brake because the distances are shorter, On a center pull, the cable stops up at the top of the calendar, and there are/were 4–5 inches of metal to get to the brake pad and then the rim. So the rider is expending a fair amount of energy moving the caliper before it ever gets to the brake and the rim. Too much energy was being expended and too little braking was being done.